Taphonomic observations on eastern Australian Cretaceous sauropods

Cretaceous (Albian–Cenomanian) sauropod body fossils are known from the Eromanga Basin of central Queensland and Surat Basin of northern New South Wales/southeastern Queensland. Most bones are uncrushed and undistorted. Associated components of the caudal and forelimb skeleton are dominant in current collections and probably derived from more complete skeletons now lost to erosion, or yet to be exposed. Dorsal and cervical vertebrae have rarely been reported and no cranial material has yet been found. None of the Australian sauropod remains shows evidence of predation or scavenging, but at least two specimens of Wintonotitan wattsi were intimately associated with plant macrofossils allowing limited inference of their postmortem environments.     

南阳麒麟岗西汉墓中出土的后石家河文化玉鹰

1989年南阳麒麟岗西汉墓M8出土了一件后石家河文化时期减地阳线纹的玉鹰残件。根据其他遗址出土或传世的类似形制遗物,对这件器物进行研究性复原。复原后发现该件玉鹰为目前已出土的后石家河文化时期尺寸最大的圆雕玉器,为探讨后石家河文化时期的玉器传播提供了新的资料。     

Seismic evidence for fluid migration pathways from an overpressured system in the South China Sea

Overpressured systems and intense, anomalously hot fluid expulsion in the Yinggehai Basin of the South China Sea offer an opportunity to understand the history of fluid flow and the process of hydrocarbon accumulation in overpressured environments. Fluid migration pathways from overpressured compartments in the basin are largely controlled by the distribution of faults and fractures. Episodic opening of these faults are related to the dynamics of an overpressured system and tectonic movements during basin evolution. At the crests of diapiric structures, fluid expulsion is seismically imaged as chimney‐ or plume‐like features, low to middle seismic amplitudes, and intermittently chaotic and blank reflecting seismic facies. These fluid pathways are controlled by vertical faults, which commonly penetrate overpressured and overlying normally pressured zones. Fluid expulsion is also observed near the main faults, such as the No. 1 Fault at the north‐eastern margin of the basin. Investigation by sidescan sonar on onshore and offshore Hainan Island indicates that there are more than 100 gas seepages adjacent to the No. 1 Fault. Migration pathways in the diapiric structures are controlled by three types of fault and fracture. Penetrative faults formed by dextral strike‐slip movement of the Red River faults commonly occur in the centre of the diapirs, and may have been a triggering factor for the diapirism, and controlled their distribution. Hydrofractures occur in certain mud‐rich layers and may have been generated by hydraulic fracturing. Radial normal faults occur at the top of diapirs and were formed by the intrusive process. These fluid migration pathways played an important role in regional hydrocarbon accumulation.     

Isotope sourcing of prehistoric willow and tule textiles recovered from western Great Basin rock shelters and caves – proof of concept

Isotope and trace-metal analyses were used to determine the origin of plants used to manufacture prehistoric textiles (basketry and matting) from archaeological sites in the western Great Basin. Research focused on strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (¹⁸O/¹⁶O) isotope ratios of willow (Salix sp.) and tule (Schoenoplectus sp.), the dominant raw materials in Great Basin textiles. The oxygen-isotope data indicated that the willow and tule used to produce the textiles were harvested from the banks of rivers or in marshes characterized by flowing water and not from lakes or sinks. The strontium-isotope data were useful in showing which plants came from the Humboldt River and which came from rivers headed in the Sierra Nevada.     

Faunal changes in farming communities from Basketmaker II to Pueblo III (A.D. 1–1300) in the San Juan Basin of the American Southwest

The San Juan Basin of the American Southwest is home to some of the best known architecture in pre-Columbian North America. Although many faunal assemblages have been reported for individual sites, there has been little synthesis of hunting and husbandry in these farming communities. In an attempt to understand changing animal usage over time in the San Juan Basin, we use three indices to investigate the usage of artiodactyls, lagomorphs and turkeys. These three taxonomic groups formed the bulk of meat diets between Basketmaker II and Pueblo III times (A.D. 1–1300). Our analysis indicates that artiodactyls declined over time in relation to lagomorphs. Turkeys increased in the northern regions when compared to lagomorphs. Cottontails increased when compared to jackrabbits over time. We suggest that as human populations increased in the San Juan Basin, artiodactyls were more intensely hunted. People then began to raise more turkeys in favorable regions, and also hunted more lagomorphs in relation to artiodactyls. Deforestation, also as a result of increased human populations, would have created conditions more favorable for cottontails than jackrabbits in many areas.     

Fluid systems and mineralization in the north German and Polish basin

The North European Basin hosts mineral deposits like the Kupferschiefer and the Mississippi Valley Type deposits in the Silesian sub‐basin in Poland. The basement to this basin, exposed in the Harz Mts and in the Flechtingen and Calvörde Blocks, contains Mesozoic Pb–Zn vein mineralization and barite–fluorite deposits as well as massive hematite veins in the Rotliegend volcanics. A comparison of the mineralizing models of these deposits with results from a basin‐wide petrographic, fluid inclusion and stable isotope study shows that the genesis of the mineral deposits can be explained by fluid systems that were active during different stages of basin evolution. These comprise syn‐ to post‐magmatic fluids derived from or mobilized in the course of the Rotliegend magmatism, fluids convecting in the Rotliegend units during the extensional basin subsidence in the Permo‐Triassic and originating from progressive devolatilization of the basin sequence and fluids derived from the overlying Zechstein evaporites. Deep‐reaching fault systems developing during the Cretaceous tectonic reactivation enhanced fluid percolation from the surface to the deep sections of the basin sequence. Identification and correlation of these fluids across the basin and in the mineralizations provide the base for a basin‐wide metallogenetic model.     

Narcissus's Mirror: Manufacture and Modernism in the American Great Basin—The Case of Pottery

The commodification of pottery cannot be reduced to strict econo-technological terms. Commodification is a cultural process, enmeshed in local, regional, and international systems of meaning. As Victorian Modernism eroded, anti-modern movements commodified traditional culture. These philosophies, themselves commodities, had repercussions on the pottery industry throughout the world. In both America and Australia, these processes produced art and studio potteries. In the American Great Basin, these changes were experienced very differently by potters from different cultures. The commodification and industrialization of modern pottery factories predicated the reification of a pre-industrial artisanal past.     

Material Modeling in the Dynamic Nonlinear Analysis for Recycled Aggregate Concrete Structures

Dynamic mechanical tests of recycled aggregate concrete (RAC) test units confined by transverse hoop reinforcement are carried out. The effects of the strain rate, hoop reinforcement confinement, and replacement ratio of recycled coarse aggregate (RCA) on the mechanical properties of confined recycled aggregate concrete (CRAC) are thoroughly analyzed and assessed. The strain-rate-dependent constitutive model of CRAC is proposed for the high strain rate representative of seismic conditions. A three-dimensional discrete numerical model, based on the proposed rate-dependent material model of CRAC, is established to investigate and evaluate the dynamic nonlinear behaviors of RAC structures.     

Groundwater age,brine migration,and large‐scale solute transport in the Alberta Basin,Canada

There is a great contrast in geochemical and hydrogeologic estimates of the residence times of pore fluids in sedimentary basins. This contrast is particularly evident in the Alberta Basin, Canada, which has served as the study area for important studies of long‐term fluid flow and transport. To address these differences, we developed two‐dimensional simulations of groundwater age, constrained by both hydrogeologic and geochemical observations, to estimate the residence time of fluids and the amount and timing of flushing by meteoric waters in the Alberta Basin. Results suggest that old, residual brines have been retained in the deepest parts of the basin since their formation ca. 400 Ma, but significant dilution by younger waters has reduced the age of these pore waters to no more than approximately 200 My. Shallower formations have been flushed extensively by fresh, young waters. Loss of brines and dilution of older pore waters occurred primarily after the uplift of the Rockies with the introduction of the gravity‐driven flow regime. Despite these large changes in flow regime, solute exchange between deep saline aquifers and the overlying vigorous freshwater flow system was found to be consistent with long‐term dispersive mixing across subhorizontal concentration gradients rather than by direct flushing. Sensitivity studies using an analytic solution supported the use of 100 m for transverse dispersivity in large‐scale numerical models. These simulations confirm that the age and origin of brines are in many cases poor indicators of long‐term solute transport rates in sedimentary basins, but the geochemical indicators that are used to determine the origin of brines can provide useful constraints for calculating groundwater age and are far more commonly available than isotopic groundwater age tracers.     

尼罗河流域文明与地理环境变迁研究

本文根据对尼罗河流域文明区地理环境变迁研究的结果,认为正是由于距今9000-4000年前亚非季风势力增强、季风雨量增加给尼罗河流域带来的湿润气候,为文明的形成和初步发展创造了优越的地理环境。因而尼罗河流域文明不仅仅是"尼罗河的赠礼",而应当更准确地说它是"季风雨的赠礼"。也正是由于季风雨的多寡在很大程度上制约着文明的盛衰,因此,由于从距今4000年前后开始的季风势力衰退和季风雨量锐减而导致的干旱化、沙漠化,则逐步吞噬了这一古老的文明。